This site is a database of mercantile vessels that sailed in the SL and SL/MKS convoy series. Currently it holds data for 32 convoys in the range SL.1 - SL.40 but eventually it will be extended to SL.176 where records exist.
Convoys will be added when time is available (
m/d/y) and you should either check the contents page or send me an email to be kept informed when additions appear. Please
read the notes before using the database. For each convoy, vessels are listed in alphabetical order but should you wish to reconstruct the 'Cruising Order' to show the disposition of the ships, you may download a blank form here (print the page in landscape mode and enter the ships' names according to their pendant numbers).

The SL series of convoy catered for vessels returning to the UK from the South Atlantic commencing from the collection point of Freetown in Sierra Leone. Initially, the series alternated between fast (SLF) and slow (SL) convoys but from January 1940 (SL.15) the fast convoys would rendezvous with the
preceding slow convoy, somewhere within European waters, in order to economise on escort vessels. This
practice was in force until January 1941 (SL.65) when the fast and slow sections were combined.

The SL convoy series commenced in September 1939 and some forty SL convoys had been escorted before the complementary OS series (UK - Freetown) began in July 1941. The SL series continued until October, 1942 (SL.125) when it was suspended for five months to free resources for Operation Torch (invasion of North Africa which began on November 8, 1942) and also to avoid crossing the US - UK convoy routes. The series recommenced in March 1943 and in April 1943 it was joined by the MKS series bound for the UK from Gibraltar. While the SL series continued until November, 1944 (SL.178), the OS series continued until May, 1945.

For each convoy I have compared the data, which is derived from original sources contained in the National Archives, with that of Hague (Arnold Hague,'The Allied Convoy System 1939-1945', ISBN 1-55125-033-0).

When available, I have included the pendant number (position in convoy), destination, cargo and nationality for each vessel in convoy. However, not all records remain and many are scanty and often hand written, particularly with the earlier convoys. Also, I have added links (to self-closing panels) giving further information on the vessels lost both within and detached from convoy. Where information was available, I have also noted any vessels that had intended to travel in convoy but did not sail since this information is also valuable when researching individual vessel movements. Often, vessels that did not sail can be found in the preceding or subsequent convoy. When available, the original port lists have been cross-checked with the cruising order chart to maintain accuracy, resolving name differences by reference to 'Der Handelsflotten der Welt 1942', ISBN 3-469-00552-4.

There is surprisingly little data available on the Internet concerning the composition of individual convoys. Data on some HX, ON, ONS and SC series (mainly North America - UK) may be found on the warsailors web site .

For OS/ KMS convoys, see the OS/
KMS section,
for convoy OS.33 see the OS.33 and for
the Main Page click here.

The author wishes to express thanks to Dominique Lemaire for diligently proofreading these convoy pages.

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